A scientist fills a large, tightly sealed balloon with 52,000 ml of krypton at STP. Using significant figures, how many moles of helium are contained within the balloon?

10 years is the answer

i wish i could but this one is weird give me abc and i can solve it.

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.